1. Field of the Invention
This invention relates to silicate foam insulating and structural compositions, and especially to a light weight, high strength, high water resistant, low shrinkage silicate foam and process for producing the foam.
2. Brief Description of the Prior Art
Aqueous silicate compositions have been used extensively in the art for specialized applications such as cements, insulation, coatings, and matrix for refractory or ablation aggregate. Silicate foam in inherently fire resistant and has excellent insulation properties. The heat transfer coefficient of silicate foam compares favorably with that of polystyrene and polyurethane foam and silicate foam has a decomposition temperature more than five times greater than these well known insulating foams.
Even with extensive work in the art, prior art silicate foam compositions have not been practical because of poor water resistance, low strength and difficulties in fabrication of a foam structure. Prior art compositions could not be practically fabricated into shapes due to composition instability and excessive shrinkage. Furthermore, these compositions could not be economically applied by commercial spraying techniques due to composition instability, difficulties in controlling viscosity and poor adhesion. Thus, there has been a need and a readily available market for a versatile silicate foam composition having a combination of high strength, good water resistance, good adhesion characteristics and acceptable fabrication characteristics.